A Global War: New Fronts, 1915-1917

The war quickly spread beyond Europe's core battlefields. The Ottoman Empire, secretly allied with Germany since August 1914, formally entered the conflict that October after its fleet bombarded Russian Black Sea ports. In 1915, poison gas made its large-scale battlefield debut when Germany released chlorine at the Second Battle of Ypres, while an Allied attempt to force the Dardanelles and knock the Ottomans out of the war, conceived chiefly by Winston Churchill, led to the Gallipoli campaign: after a failed naval assault in March 1915, Australian and New Zealand troops landed at what became known as Anzac Cove on April 25, 1915, facing fierce resistance led by the Ottoman officer Mustafa Kemal, and the campaign was finally abandoned in a skillful evacuation over the winter of 1915-16.